Tropical Depression MELISSA

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TROPICAL DEPRESSION MELISSA DISCUSSION NUMBER 9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL142007
1100 AM EDT SUN SEP 30 2007
STRONG WESTERLY SHEAR HAS TAKEN ITS TOLL ON MELISSA. AFTER MOST OF
THE CONVECTION DISSIPATED ABOUT 12 HOURS AGO...THE CYCLONE HAS ONLY
BEEN ABLE TO GENERATE SMALL PULSATING BURSTS OF CONVECTION THAT
HAVE EACH LASTED ABOUT 3 HOURS. AN 0818 UTC QUIKSCAT PASS SUGGESTS
THAT THE CIRCULATION HAS BECOME LESS-DEFINED. VISIBLE SATELLITE
IMAGERY REVEALS THAT WHATEVER CENTER REMAINS IS TO THE SOUTH OF
THE PREVIOUS ESTIMATES...REQUIRING A RELOCATION FOR THIS ADVISORY.
THE QUIKSCAT DATA SHOW THAT THE WINDS HAVE DECREASED TO ABOUT 25 KT
AND MELISSA IS DOWNGRADED TO A TROPICAL DEPRESSION.
THE INITIAL MOTION ESTIMATE IS 285/11. SINCE MELISSA IS BECOMING A
SHALLOW SYSTEM IT SHOULD BE STEERED WEST-NORTHWESTWARD BY THE
LOW-LEVEL RIDGE OVER THE EASTERN ATLANTIC DURING THE NEXT DAY OR
SO. THEREAFTER...THE CYCLONE IS EXPECTED TO TURN NORTHWESTWARD
AROUND THE WESTERN PERIPHERY OF THIS RIDGE. THE TRACK FORECAST HAS
BEEN SHIFTED SOUTHWARD MAINLY DUE TO THE RELOCATION...AND IS CLOSER
TO THE HWRF AND GFDL SOLUTIONS.
THE ENVIRONMENT AHEAD OF MELISSA IS EXPECTED TO REMAIN HOSTILE AS
WESTERLY SHEAR IS FORECAST TO PERSIST. THE INTENSITY FORECAST
MAINTAINS MELISSA AS A TROPICAL DEPRESSION DURING THE NEXT DAY OR
SO. HOWEVER...IF THE CIRCULATION CENTER CONTINUES TO BECOME
LESS DEFINED AND THE DEPRESSION DOES NOT GENERATE ENOUGH ORGANIZED
CONVECTION...IT COULD BECOME A REMNANT LOW MUCH SOONER.
FORECAST POSITIONS AND MAX WINDS
INITIAL 30/1500Z 16.1N 32.6W 25 KT
12HR VT 01/0000Z 16.7N 34.3W 25 KT
24HR VT 01/1200Z 17.7N 36.5W 25 KT
36HR VT 02/0000Z 18.8N 38.9W 25 KT...REMNANT LOW
48HR VT 02/1200Z 20.2N 40.8W 20 KT...REMNANT LOW
72HR VT 03/1200Z 23.5N 43.5W 20 KT...REMNANT LOW
96HR VT 04/1200Z...DISSIPATED
$$
FORECASTER BROWN
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